The Drowned Earth: 4000 AD, After The Thaw
What happens when all the polar ice melts? What would the world map look like after a maximum sea level rise? And how long does it take to get there? These are interesting questions now that climate change is – finally – on the political agenda. And as a cartographer, I could not resist the temptation to visualize the worst case scenario.
When the Greenland ice sheet melts, the sea level rises 7 meters, when the ice melts in Antarctica it causes a rise of 58 meters. So together that makes 65 meters. But that is an average.
Because something else plays a role: gravity. Such a lump of ice has a large mass and pulls the seawater towards it. When that attraction is no longer there, most of the sea level rise will take place on the other side of the world.
When the Greenland ice melts, here in Western Europe we’ll have relatively little trouble with that, because Greenland is nearby. But Antarctica is much further away. When the ice melts there, the sea level in the northern hemisphere is likely to rise much more than 65 meters.
There are more uncertain factors that imply you can’t simply take the 65-meter elevation line as the new coastline. When the ice melts, the land beneath it will rise up, for example. But former land that suddenly has a load of water on it will be pushed down. And if the sea level does not rise too quickly, the land can grow with it, because seas and rivers deposit sediments.
My sea level rise map is therefore an approximation. On average I have taken those 65 meters, but with a correction for the gravity effect: a little more rise in the northern hemisphere, a little less in the south.
The drowned land of Europe
Remarkably, the world map in general does not change as dramatically as one might expect. 95 percent of the land surface remains above sea level. Africa stays almost completely intact, Australia and South America only get a few inland seas. And just a few large bites are taken from Asia and North America.
But the ramifications for Europe are far-reaching. Our continent is no longer an attachment to Asia, but a bizarrely shaped archipelago. London, Rotterdam, Copenhagen, Hamburg, Saint Petersburg: only some skyscrapers protrude above the water, with concrete reefs and perhaps some floating settlements around them .
Good and bad news
The good news is that those ice caps won’t melt in a few years, or even a few decades or centuries. After the last ice age, the sea level rose approximately three meters per century. At that rate, it will take until 4000 AD before the world map will look like this.
The bad news is that a rise of a few meters would already be quite hard to handle. Too put it mildly.
In the Netherlands, for example, it is becoming increasingly difficult to get the water of the Rhine and Meuse to the North Sea in an orderly manner. At the same time, it is getting harder and harder to prevent the salty seawater from seeping into the country. No dike is gonna stop that.
Nothing can be said with certainty about the consequences of the rise in temperature and sea level for landscape and vegetation. But let’s be optimistic. When the temperature rises, precipitation will increase worldwide, so some deserts may turn a little bit greener. Australia in particular, with its two new inland seas, could benefit from this effect.
After the great thaw, Greenland and Antarctica become a kind of Scandinavia, with vast pine forests and, allright, still a few glaciers. Siberia, now largely a no-go area, will have a much milder, locally even Mediterranean climate. Hopefully, by then, Russia will be ruled by friendlier people than there we find in the Kremlin today.
In fact it looks pretty interesting, this world in 4000 AD, with its maximum water levels. You’d almost want to fast forward to take a look there. But consider the losses. It may be only five percent of the current land masses, but a large part of the world’s population lives there. Low-lying coastal areas are simply popular places to live.
In the Netherlands the coastline will shift to Heerlen-on-Sea in the deep south. The country will be reduced to a few dozen square kilometres. Hopefully, Greenland and Antarctica will welcome the flood refugees generously when the time comes.
It is also quite a hassle, by the way, to constantly build new coastal towns with boulevards and beaches and marinas and to have to give up within a century. And that over and over again for two millennia.
No, let’s try to keep warming under control. And let’s leave the terraforming for Mars.
Further reading: is there really no planet B?